Projector

1. A projector comprising: a light source to emit light; an optical structure constituting an optical system to modulate or combine emission light of the light source; a projection element to project exit light from the optical structure; a flow passage to flow a cooling liquid for cooling the light source; and a housing forming an exterior of the projector, the flow passage having a first connection flow passage connected to the light source, a heat-releasing flow passage disposed on the housing, a second connection flow passage connected to the light source, the first connection flow passage connected to one end of the heat-releasing flow passage, the other end of the heat-releasing flow passage connected to the second connection flow passage.

2. The projector according to claim 1 , further comprising: a pump to circulate the cooling liquid in the flow passage.

3. The projector according to claim 1 , the heat-releasing flow passage being formed by the housing and at least one member joined to the housing, and formed by providing a space to circulate the cooling liquid between the housing and the member.

4. The projector according to claim 1 , a heat-releasing fin being provided in an outer surface of the housing.

5. The projector according to claim 1 , the heat-releasing flow passage being formed protruding in an outer surface of the housing and serving also as a heat-releasing fin.

6. The projector according to claim 1 , an aperture for maintenance being provided in a position of the housing opposed to the light source and the optical structure, a cover member covering the aperture being provided, the heat-releasing flow passage being provided around the aperture.

7. The projector according to claim 1 , the housing including a first housing member and a second housing member, a heat-releasing flow passage being provided on the first housing member, the light source and the connection flow passage being provided on the second housing member, an aperture for maintenance being provided in a position of the first housing opposed to the light source and the optical structure, a cover member covering the aperture being provided, the heat-releasing flow passage being provided around the aperture.

8. The projector according to claim 1 , the housing including a first housing member and a second housing member, the first housing member having the heat-releasing flow passage, the connection flow passage and the light source.

9. The projector according to claim 1 , the housing including a first housing member and a second housing member, the first housing member having the heat-releasing flow passage, the connection flow passage, the light source, the optical structure and the projection element.

10. The projector according to claim 1 , the housing including a first housing member and a second housing member, the first housing member having the heat-releasing flow passage, the connection flow passage, the light source and the optical structure, the second housing member having the projection element, a positioning mechanism being provided to position the first housing member and the second housing member in position so that the optical structure and the projection element can be aligned during assembling the first housing member and the second housing member together.

11. The projector according to claim 8 , the housing including a first housing member and a second housing member, the first housing member having a pump to circulate the cooling liquid in the flow passage.

12. The projector according to claim 7 , the first housing member configures an upper part including at least a top surface of the housing, the second housing member configuring a lower part including at least a bottom surface of the housing, at least the heat-releasing flow passage being provided on the first housing member.

13. The projector according to claim 1 , a heat-conductive member being provided to conduct heat generated at the optical structure to the connection flow passage.

14. The projector according to claim 1 , the light source having a light-emitting element or a light-emitting element array as a light source.

15. The projector according to claim 1 , the light source having a light-emitting element, a light-emitting element base firmly fixing the light-emitting element, an inlet passage in the light-emitting element base for the cooling liquid to cool the light source, and an outlet passage, the inlet passage and the outlet passage being provided generally parallel with a plane of the light-emitting element base on which the light-emitting element is firmly fixed.

16. The projector according to claim 1 , a grip member to grasp the projector main body being provided on the housing.

17. The projector according to claim 1 , having a grip to grasp the projector main body on the housing, the heat-releasing flow passage being provided around the grip.

18. The projector according to claim 17 , a grip member to grasp the projector main body being provided on the grip.

19. The projector according to claim 17 , the grip being provided with an aperture for maintenance and a cover member covering the aperture.

20. The projector according to claim 1 , having a support to support the heat-releasing flow passage in the housing, the heat-releasing flow passage being pressure-fit and fixed in the support.

21. The projector according to claim 20 , the heat-releasing flow passage being arranged in the support, and fixed in the support by expanding the heat-releasing flow passage by a high-pressure fluid.

22. The projector according to claim 20 , a heat-conductive member to conduct heat being provided and fixed between the support and heat-releasing flow passage.

23. The projector according to claim 1 , comprising: a support member supporting the heat-releasing flow passage and a support to support the support member on the housing, the support member being pressure-fit with the heat-releasing flow passage and fixed in the support.

24. The projector according to claim 23 , the support member and the heat-releasing flow passage being arranged in the support, and fixed in the support by expanding the heat-releasing flow passage by a high-pressure fluid.

25. The projector according to claim 23 , a heat-conductive member to conduct heat being provided and fixed at least one of between the support area and the supporting member and between the support member and the heat-releasing flow passage.

26. The projector according to claim 1 , the heat-releasing flow passage being formed within a main body of the housing.

27. The projector according to claim 1 , the heat-releasing flow passage being inserted in a main body of the housing.

28. The projector according to claim 1 , the housing being structured by a main housing member and a sub housing member, a plurality of through-holes being formed within a main body of the main housing member, the heat-releasing flow passage being structured by joining the main housing member and the sub housing member together.

29. The projector according to claim 28 , the main housing member being provided, at an end, with a plurality of grooves connecting the plurality of through-holes, the heat-releasing flow passage being structured by joining the main housing member and the sub housing member together.

30. The projector according to claim 28 , a plurality of grooves to connect the through-holes being provided in the sub housing member in positions opposed to the plurality of through-holes of the main housing member, the heat-releasing flow passage being structured by joining the main housing member and the sub housing member together.

31. The projector according to claim 1 , the flow passage having the connection flow connected to the light source, the connection flow passage continuing to the heat-releasing flow passage to a second connection flow passage, and then to the light source.

32. The projection according to claim 31 , the connection flow passage and the second connection flow passage being the same.